The Affordable Care Act (ACA) allowed states to expand Medicaid coverage to low-income childless adults, many of whom receive specialty mental health and substance use services through community mental health systems. Leading up to the passage of the ACA, community mental health providers and their professional associations were generally supportive of expanding Medicaid under the ACA. Medicaid covers specialty services central to quality mental health and substance use care, as well as other physical health services that many in the serious mental illness (SMI) and substance use disorder (SUD) populations lacked before 2010.

To date, 32 states have expanded Medicaid (including the District of Columbia), while the remaining 19 have not. This brief, which was developed with support from the Commonwealth Fund, examines the impact of the ACA on public mental health and substance use systems in three Midwestern states: Michigan and Indiana, both Medicaid expansion states, and Wisconsin, a non-expansion state.

The experience from these three states suggests that Medicaid expansion has had an important and overall beneficial effect in particular for the substance use population. The favorable impact is particularly important in light of the opioid epidemic.